Browsing by Subject "Mice"
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Item A comparison of proteins synthesized and secreted by peri-implantation embryos of rats and mice(Texas Tech University, 1992-08) Liu, Shao-tungPsychoyos (1973) has defined embryo implantation in rodents as the result of coordinated interactions between a uterus that is "receptive" and an embryo that has reached the "blastocyst stage" of development. In rats and mice, uterine "receptivity" is vaguely understood as the ability of the endometrium to undergo decidualization and formation of the maternal plancenta; it is achieved only after exposure to ovarian hormones secreted in a specific sequence (Psychoyos 1976) . The process of decidualization involves profound changes in both morphological and biocherical characteristics of the endometrial stroma including a localized increase in vascular permeability and tissue edema, increased rates of cell proliferation, differentiation of stromal cells into so-called "decidual cells," and increases in synthesis of DNA, RNA and protein (De Feo 1967 and Finn 1977). Because decidualization only occurs in areas adjacent to the blastocysts and can be observed even before their attachment to the uterus, it is believed that a soluble factor from the embryo must exist which acts as a signal to trigger the reaction. Although the nature of the soluble factor has not been determined, it has been proposed at one time or another that steroids, histamine, prostaglandins or proteins from the embryos are responsible (see Kennedy 1983; Weitlauf 1988, for reviews).Item A study of olfactory discrimination in neonatal mice (Mus musculus): neonate ultrasounds as a function of the source of soiled nesting substrate(Texas Tech University, 1976-05) Plumlee, Gary G.Not availableItem Absorption and tissue deposition of 51 chromium and 75 selenium from brewer's yeast in the mouse(Texas Tech University, 1982-05) Holland, Paula NellNOT AVAILABLEItem Biosystematics of the genus Reithrodontomys on the Southern High Plains(Texas Tech University, 1995-08) Lynch, Maryann RoseDetermining and understanding evolutionary relationships of organisms is a goal in systematics. Initial studies of the genus Reithrodontomys addressed the subspecific affinities of species within the genus in portions of their ranges (Hooper 1952; Jones and Mursaloglu 1961). The focus of subsequent investigations has evolved beyond the taxonomic level of the subspecies, and has paralleled the development of new genetic and molecular techniques, such as standard karyotype analysis (Shellhammer 1967; Carleton and Myers 1979; Engstrom et al. 1981), G- and C- banding of chromosomes (Robbins and Baker 1980), starch-gel electrophoresis of allozymes (Arnold et al. 1983), and most recently, in situ hybridization of satellite DNA (Hamilton et al. 1990). Thus, many of the questions regarding Reithrodontomys pertain to phylogenetic relationships. Despite the many studies of Reithrodontomys, important questions relative to variation among populations of species within the genus remain unanswered. Reithrodontomys megatotis, from the Southern High Plains in West Texas, represents a taxon in which variation within and among populations is not well understood. This species Is a relatively rare or elusive inhabitant of the area, and to date, these characteristics have prevented a thorough study of populational differences in this geographical region. Currently, two subspecies (R m. aztecus, R. m. megatotis), are recognized rom this expanse in West Texas. The purpose of this study is to examine specimens from this region, and through the use of phenetic techniques and statistical analyses, elucidate the extent of nongeographic and geographic variation in R. megatotis, and assess the subspecific status of R. megatotis on the Southern High Plains.Item Characterization of allergic effects induced by a Penicillium chrysogenum conidia-asssociated allergen in a murine model(Texas Tech University, 2002-05) Schwab, Christopher JaySick building syndrome (SBS) and allergic asthma have been dramatically increasing since the 1970s in developed nations. SBS describes various symptoms resulting from indoor air quality (lAQ) problems, including allergic rhinitis, headaches, itchy eyes, and tightness of the chest. Several studies have reported the association of damp buildings as well as the presence of molds with cases of asthma and other respiratory symptoms, including SBS-related complaints. Recent evidence by our laboratory has shown the association of SBS with the presence of certain strains of fungi, especially Penicillium chrysogenum, and viable P. chrysogenum conidia or spores were shown to induce allergic inflammation when introduced into mice. Further research was needed to define the effects of fungal spores from sick buildings on the immune system. Other researchers have characterized allergens from P. chrysogenum and related fungi, however, these allergens were isolated from whole cell cultures and not from spores. The goals of this study were to extract allergens from viable P. chrysogenum spores and characterize allergic effects induced by those allergen extracts using a murine model. As a result of this study, we present evidence that viable P. chrysogenum spores secrete previously uncharacterized allergens with proteolytic activity. These spore-associated protease extracts, which we have designated Pen ch, induced allergic effects in a murine model in this study. C57BL/6 mice sensitized to and challenged with the protease extract produced high levels of IgE and IgG1 specific to the protease allergens and spores from the organism. Mice sensitized to the protease extracts also developed perivascular eosinophilia of the airways that was associated with significant production of eotaxin. In addition, protease extract-sensitized mice developed hyperplasia of mucus producing cells in the airways as well as perivascular inflammation by neutrophils. The data presented m this study indicate that chronic exposure and sensitization to protease allergens released by viable P. chrysogenum spores in vivo induces a strong allergic inflammatory response m a murine model. In buildings contaminated with high levels of P. chrysogenum spores, allergic symptoms occurring m individuals could be the result of inhalation of viable P. chrysogenum spores due to sensitization to the protease allergens characterized in this study. The results of this study should lead to further studies regarding the mechanism of allergic effects induced by P. chrysogenum spore-associated protease allergens and the development of treatment options for people exposed to these allergens.Item Chromium and yogurt effects on glucose, insulin and hepatic lipid in obese mice(Texas Tech University, 1984-12) Li, Yi-chingDietary chromium (Cr) supplements in casein or yogurt-based diets were fed to genetically obese C57BL/6J-OB (ob/ob) mice. Diet groups were casein negative control (C), yogurt negative control (Y), enriched yogurt (EnY), medium chromium yogurt (MCrY), high chromium yogurt (HCrY) (1.83 ppm), and high chromium casein (HCrC) (1.85 ppm). Food and water were available ad libitum and no significant differences were observed in final body weight. In obese mice total hepatic lipid was significantly greater in the C than in the HCrC group and in the Y than in the HCrY group. Plasma immunoreactive insulin levels tended to be lower in animals fed HCrC and HCrY diets. Insulin/glucose ratio was significantly higher in the C group than in the HCrY group indicating that more insulin was required in the negative control group to handle an equivalent quantity of glucose. In the obese mouse, a model for insulin resistance, Cr supplementation apparently affects both hepatic lipid deposition and insulin/glucose ratio.Item Effect of dietary selenium and fat on the incidence of spontaneous mammary tumorigenesis of Cb3sH/StHa mice(Texas Tech University, 1985-12) Stoltenberg, PeggyThe purpose of this present study was to combine two dietary variables (Se 0, 0.1, 1.0 ppm and polyunsaturated fat as safflower oil or saturated fat as coconut oil) and observed the incidence and development of spontaneous mammary tumors in C-.H/StHa mice.Item Effect of selenium, riboflavin, and vitamin E on oxygen radical production and cytotoxic activity of peritoneal macrophages of Balb/c mice(Texas Tech University, 1994-05) Kang, ChunranIn nutrition science, we learn that many foods that are healthful in reasonable portions can also lead to ill health when eaten in excess. One can eat too much of almost anything. For example, vitamin A as retinol, when consumed in excess, has toxic effects, however, this vitamin is also clearly an essential nutrient for vision (Olson, 1984). When we realize that water is the most essential of the nutrients, since we cannot survive much longer than three days without it, then consider that without oxygen human beings will live less than a few minutes. However, at any level of dietary supplementation meeting essential requirements, oxygen is both toxic and carcinogenic. In this context oxygen demonstrates major toxicity and carcinogenicity at the same levels which are required for support of life. Oxygen toxicity can cause many cellular dysfunctions, including deactivation of essential enzymes by oxidation, with primary effect on the oxidation of cysteine thiols producing disulfides. It also involve effects of cellular mediators and secretions (Huber and Drath, 1981), and lipid peroxidation (Allen et al., 1973). The toxicity of lipid peroxides by disruption of the cellular membrane is the primary mediators of oxygen toxicity. Therefore, the basic schemata for lipid peroxidation functions as follows.Item Electrophoretic Analysis of the Peromyscus Truei Group (Rodentia, cricetidae) in Texas and New Mexico(Texas Tech University, 1972-05) Johnson, Gerald LeeNot Available.Item Evaluation of the Light Emission Kinetics in Luciferin/Luciferase-Based In Vivo Bioluminescence Imaging for Guidance in the Development of Small Animal Imaging Study Design(2006-05-15) Bollinger, Robert Albin; Mason, Ralph P.Bioluminescence imaging (BLI) is gaining acceptance as a small animal imaging modality useful for visualizing cellular and molecular activity in vivo, and especially for evaluating tumor development and efficacies of treatments. Various studies have validated the technique for a number of purposes, including the quantification of tumor burden; however, many basic questions have not been investigated whose answers may ultimately impact the conclusions drawn from the results. Primarily, consideration of the impact of BLI emission kinetics has not been rigorously addressed. This study provides information on the effects of different routes of luciferin substrate injection on the BLI kinetic profile, including time to peak emission, magnitude of peak emission, and emission decay characteristics. This study also presents for the first time the use of subcutaneous (s.c.) luciferin injection and the use of s.c. luciferin injection followed by continuous s.c. infusion (s.c.i.) for establishment of stable BLI light emission. Further, results are presented of the kinetic profile changes associated with 1) inhaled and injected anesthesia; and 2) ambient air heating on mouse core temperature. The study demonstrated substantial differences in the peak light emission with i.v. providing the highest, with s.c., s.c.i. and i.p yielding 30% or less of the light emission of the i.v. route. The correlations between tumor burden and BLI light emission were moderately strong (R>0.75) for each administration route, but at varying times following injection, providing information for establishment of optimal image start times. Surprisingly, ambient cooling of the animal while under anesthesia yielded peak light emissions of up to 100% higher than those obtained when ambient air heating was used to maintain mouse core temperature. Finally, guidelines are presented to aid investigators in development of BLI study design to give due consideration to luciferin administration routes, anesthesia protocol, and animal temperature maintenance.Item Evolutionary and genetic studies of selected populations of Deer Mice (Peromyscus maniculatus) and Black Eared Mice (Peromyscus melanotis)(Texas Tech University, 1973-05) Bowers, James HoytNot availableItem Identification of cubilin (p400) as galectin-3 binding protein from the murine utero-placental complex(Texas Tech University, 2000-12) Crider-Pirkle, Sunday Suzanne; Faust, Charles; Weitlauf, Harry M.; Hardy, Daniel; Lee, Vaughan H.; Webster, Daniel R.; Whelly, Sandra M.Galectin-3 is a soluble p-galactoside binding lectin that is present in several cell types within the uteroplacental complex (UPC) of mice. Affinity chromatography with immobilized galectin-3 was used to isolate potential binding partners for the lectin from homogenates of UPC. At least one glycoprotein (Mr 400,000; p400) was isolated that bound galectin-3 in a carbohydrate-dependent manner. Exposure of p400 to glycosidases decreased its apparent size by 10%. Differential migration of p400 in nonreducing and reducing conditions demonstrated that the protein contains intramolecular disulfide bonds. Amino acid sequencing revealed similarity to cubilin, a 400 kDa endocytic receptor. Collectively, the molecular size of p400, its degree of glycosylation, the presence of intramolecular disulfide bonds, and amino acid sequence similarity strongly suggest that p400 is the murine ortholog of cubilin. Immunohistochemistry revealed that cubilin (p400) was present in the yolk sac epithelium from day 8 to term. It was also localized in the perforin-positive granules of uNK cells in metrial gland and decidua basalis. Although cubilin is best known as the receptor for intrinsic factor-vitamin B12 in the ileum, it may also act as an endocytic receptor in the kidney and yolk sac where it presumably mediates transcytosis of multiple ligands. The localization of cubilin to uNK cells is the first demonstration of the protein in an immune or non-epithelial cell type. However, the questions of whether cubilin actually interacts with galectin-3 in vivo, and what role cubilin plays, cannot be answered from our results. Because both galectin-3 and cubilin are present in uNK cells, one intriguing hypothesis is that they interact to modulate the immune function of uNK cells, and thus, that they are a part of a mechanism for protecting the fetus from immune rejection.Item Interaction of insulin like growth factor-1 and resistance training on skeletal muscle mass and function(2002) Lee, Suk-Ho, 1968-; Farrar, Roger P.In the present study, the effects of IGF-1 overexpression, resistance training and their interaction on muscle mass and function were examined in both mouse and rat models. In addition, the effect of IGF-1 overexpression on the reversal of training-induced adaptations in skeletal muscle mass and function during varying lengths of detraining was measured. The resistance training consisted of a ladder climbing protocol. Overexpression of IGF-1 was localized to one hindlimb via injections containing adeno-associated virus and the contralateral hindlimb served as an internal control. IGF-1 overexpression alone resulted in an increase in mass and peak tetanic tension (Po) of the flexor hallucis longus (FHL) muscle in both rat and mouse model. Eight weeks of resistance training alone resulted in an increase in mass and peak tetanic tension (Po) of the flexor hallucis longus (FHL) muscle only in rat model. The combination of resistance training and IGF-1 overexpression resulted in further increase in muscle mass and Po in rat model, giving evidence of an additive effect. Overexpression of IGF-1 significantly attenuated the loss of muscle mass in FHL during 12 weeks of detraining. These data suggest a beneficial effect of combination of resistance training and IGF-1 overexpression on skeletal muscle mass and function.Item Loss of Ventromedial Hypothalamic Leptin Receptors Results in Increased Adiposity and a Metabolic Syndrome(2008-05-12) Bingham, Nathan Christian; Parker, Keith L.Obesity is a leading health problem here in the United States and in other developing countries. Obesity is a risk factor for several life-threatening conditions including Type II diabetes, hypertension, and cardiovascular disease. Given the growing obesity epidemic, understanding the mechanisms whereby the central nervous system monitors and regulates energy homeostasis has become a major focus of scientific research in the last several decades. The discovery that mice fed a low fat diet exhibit significantly increased adipose mass with no difference in weight compared to wild-type littermates. Further, these mice exhibit a metabolic syndrome including mild steatosis, dyslipidemia, and hyperleptinemia. From a young age, Lepr KOleptin, an adipocyte-derived hormone, acts on the brain to suppress appetite and stimulate energy expenditure greatly extended our understanding of such mechanisms. The leptin receptor is expressed in a number of hypothalamic nuclei known to play a role in energy homeostasis. While much work has focused on leptin's actions in the arcuate nucleus, other sites have received substantially less attention. Here, I report that mice lacking leptin receptors within the ventromedial hypothalamic nucleus (Lepr KOVMH) develop increased adiposity and a metabolic syndrome. Lepr KOVMH mice fed high fat rodent chow show an increased sensitivity to diet-induced obesity, while Lepr KOVMH mice are hyperinsulinemic and eventually become glucose intolerant. These data demonstrate that Lepr KOVMH mice are a novel genetic model of obesity and may be used for the study of energy partitioning, lipogenesis, and central leptin signaling.Item Molecular evolution in Microtus from Chernobyl(Texas Tech University, 1997-05) DeWoody, James AndrewThe Chernobyl disaster offers a unique opportunity to study the biological effects of pollution on resident mammals. Specifically, there are three hypotheses that can be tested using nuclear genetic data. First, are levels of genetic diversity (number of alleles per locus) similar in zone and control populations? Second, is the occurrence of rare or private alleles more common in zone populations? Third, do allele frequencies at individual loci differ among populations? Each question effectively serves as a null hypothesis, e.g., that there are no differences between zone and control populations. If the contaminated environment near Chernobyl is affecting resident populations, there should be differences in some or all of these parameters. Each of the three questions listed above will be addressed using both protein and DNA data.Item Motor learning and neuroplasticity in an aged mouse model of cerebral ischemia(2011-08) Tennant, Kelly A.; Jones, Theresa A.; Mauk, Michael; Dunn, Andrew; Monfils, Marie; Gore, Andrea; Schallert, TimothyStroke is the leading cause of long-lasting disability in the United States and disproportionately affects adults in later life. Age-related decreases in dexterity and neural plasticity may contribute to the poorer prognosis of older stroke survivors, even following rehabilitative physical therapy. The goal of these dissertation studies is to determine how the cortical plasticity underlying motor skill learning, both before and after brain injury, changes in the aged brain. The general hypothesis of these studies is that age-related changes in motor performance and the limited ability to regain function following brain injury are associated with dysfunctional plasticity of the forelimb representation in the motor cortex. This hypothesis was tested in intact C57BL/6 mice by training them on a skilled reaching task and deriving intracortical microstimulation evoked motor cortical representations of the forelimb to determine training-induced changes in the function of the motor cortex. After ischemic lesions, age-dependencies in the effects of rehabilitative training in skilled reaching on forelimb motor cortical representations were investigated. Prior to injury, intact young and aged mice learned a skilled reaching task in similar time frames and with similar success rates. Training-induced reorganization in the young mouse motor cortex occurred in the caudal forelimb area, which is homologous to the primary motor cortex of primates. However, the rostral forelimb area, a potential premotor cortex, was larger in aged mice compared to young mice. Following focal ischemic lesions of the forelimb area of the sensorimotor cortex, aged mice had larger lesions and were more impaired than young mice, but both groups regained reaching ability after 9 weeks of rehabilitative training. Post-operative training resulted in plasticity of the rostral forelimb area in young mice, but we failed to see reorganization in the forelimb map of aged mice following rehabilitative training. These dissertation studies suggest that more severe brain damage in response to ischemia leads to poorer outcome in aged animals. Although the reorganization of motor cortex following initial skill learning and relearning following brain damage changes with age, the ability to learn motor tasks and improve function with rehabilitative training is maintained in healthy aging.Item Mucosal HIV-1 Transmission In Humanized Mice(2008-05-13) Denton, Paul Wesley; Garcia-Martinez, J. VictorHIV-1 infects ~6,800 people each and every day, transmitting predominantly through unprotected sexual contact. On a global scale, vaginal transmission now accounts for more than half of newly acquired HIV-1 infections. In developed countries intrarectal infection represents a major form of HIV-1 transmission. The social and economic toll of this disease has created an urgency to develop and implement novel approaches capable of preventing HIV-1 transmission. Yet this process has been hindered by the lack of adequate small animal models for pre-clinical efficacy and safety testing. Given the importance of mucosal HIV-1 transmission, the susceptibility of humanized mice to intrarectal and intravaginal HIV-1 infection was investigated. Human lymphocytes, including CD4+ T cells, generated in situ from hematopoietic stem cells reconstitute the gastrointestinal tract and the female reproductive tract of Bone marrow Liver Thymus (BLT) mice. The presence of human CD4+ T cells in these mucosal tissues renders BLT mice susceptible to both intrarectal and intravaginal HIV-1 transmission. Mucosally transmitted HIV-1 disseminates systemically in BLT mice. Effects of disseminated HIV-1 infection include a systemic loss of CD4+ T cells, particularly in gut associated lymphoid tissue, which closely mimics what happens in HIV-1 patients. The utility of humanized mice to study mucosal HIV-1 transmission is particularly highlighted by the demonstration herein that pre-exposure prophylaxis with antiretroviral drugs can prevent intravaginal HIV-1 transmission. This experimental finding has important implications for the clinical implementation of antiretroviral-based pre-exposure prophylactic measures to prevent the spread of AIDS. The goal of this dissertation project was to determine the suitability of the BLT mouse to serve as an animal model of HIV-1 transmission and as a model for assessing interventions aimed at preventing HIV-1 transmission. My conclusions are that BLT mice are susceptible to both intrarectal and intravaginal HIV-1 transmission and that pre-exposure prophylaxis with FDA approved antiretroviral drugs does prevent vaginal transmission in BLT mice. Thus, the BLT mouse system is an excellent candidate for pre-clinical evaluation of both microbicides and pre-exposure prophylactic regimens to prevent mucosal HIV-1 transmission.Item Narrowing of the SLES1 Internal Reveals Complex Epistatic Interactions in the Suppression of Autoimmunity(2010-05-14) Belobrajdic, Katherine Ann; Walkeland, Edward K.Sle1 is a potent susceptibility locus for spontaneous systemic autoimmunity derived from the NZM2410 mouse strain. The NZW-derived suppressive modifier locus, Sles1, specifically prevents the spontaneous loss in tolerance mediated by the B6.Sle1 congenic. Sles1 had previously been fine-mapped to a remarkably gene-rich region on murine chromosome 17 containing nearly 70 genes. A series of mouse strains were constructed with a variety of suppressive and non-suppressive variants of Sles1 on the B6.Sle1 genomic background which have revealed multiple layers of epistatic gene interactions within the Sles1 interval. Phenotyping of a truncated recombinant interval mapped the Sles1 phenotype to an approximately 638 KB segment, which combined with genomic and expression analysis, suggested Btnl2 and the H2 genes are strong candidates for Sles1. Finally, further characterization of the Sles1 interval has revealed an allele-specific and tissue-specific reduction of major histocompatibility complex (MHC) Class II molecules on the surface of B cells, as well as a possible role for follicular helper T cells in the development of Sle1-mediated autoimmunity. Understanding how Sles1 and other modifiers suppress systemic autoimmunity will reveal important insights for developing therapeutic strategies for systemic lupus eythematosus (SLE).Item Non-geographic variation in the dark kangaroo mouse, Microdipodops megacephalus megacephalus from Nye County, Nevada(Texas Tech University, 1967-08) Schitoskey, FrankNot availableItem Origin and Function of CD8 T Cells in MHC Class Ia-Deficient Mice(2005-12-20) Su, Jie; Forman, JamesB6.H-2Kb-/-Db-/- (DKO) mice are devoid of class Ia but express normal levels of class Ib molecules. They have low levels of CD8 T cells in both the thymus as well as peripheral T cell compartments. Although the percentage of splenic CD8aa T cells is increased in these animals, approximately 90% of CD8 T cells are CD8abeta TCRabeta . In contrast to B6 animals, most of the CD8 T cells from these mice have a memory phenotype (CD44hi) including both CD8abeta and CD8aa subsets. In the thymus of DKO animals, there is a decrease in the percentage of single positive CD8 T cells, although most are CD44low, similar to that seen in B6 mice. Our results indicated that the paucity of CD8 T cells in DKO mice might be in part due in reduced thymic export, lower basal proliferation, high apoptosis, and inability to undergo homeostatic expansion. DKO mice have greatly reduced numbers of mature CD8abeta T cells in their periphery. However, these non class Ia selected CD8abeta cells are able to mediate immune responses to a number of pathogens. Approximately 60% of the CD8abeta T cells in the spleen and peripheral lymph nodes of na?DKO mice display a memory (CD44hi) phenotype. To investigate the origins of these non class Ia selected CD8abeta CD44hi cells, we traced the phenotype of recent thymic emigrants (RTEs) and found that most were CD44lo. We also determined if their appearance was thymus dependent and found that only a small percentage of non class Ia selected CD8abeta CD44hi cells develop in a thymus-independent pathway. Functionally, CD8abeta CD44hi cells from DKO mice are able to secrete IFN-gamma in response to interleukin (IL)-12 and IL-18 in the absence of cognate antigen. When challenged with anti-CD3 in vivo, nearly half of these cells produce IFN-gamma within 3 hours. When purified CD8abeta CD44hi cells from Thy1.2.DKO mice were transferred into Thy1.1 DKO recipients and then challenged with Listeria monocytogenes (LM), an antigen specific anti-LM response was observed six days later. Our data suggest that non class Ia selected CD8abeta CD44hi cells in na?animals can respond to antigen and play a role in the innate as well as the early phase of the acquired immune response.